Ryan Bond was last seen at Preston railway station on August 12 and police believe he is in the Kendal area.
When he was last seen in Preston the 16-year-old was wearing a grey top, grey jogging bottoms and grey jacket.
Eyan is described is 5ft tall and Cumbria Police have asked him to get in touch to let them know he is he is safe and well.
Officers believe he may be with two other teenagers from the Kendal area who have disappeared.
Joshua Broome, 15, was last seen at his home in Kendal on August 14 and is described as of slim build with dark hair.
And 14-year-old William Stephenson-Coulton was last seen at his home in Kendal the following day.
He is said to be of slim build with dark-brown wavy hair.
If you have seen any of tghe boys call Crimestoppers anonymously on 0800 555 111